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-rwxr-xr-xsrc/dhcp.c1002
1 files changed, 1002 insertions, 0 deletions
diff --git a/src/dhcp.c b/src/dhcp.c
new file mode 100755
index 0000000..335fc04
--- /dev/null
+++ b/src/dhcp.c
@@ -0,0 +1,1002 @@
+/* dnsmasq is Copyright (c) 2000-2009 Simon Kelley
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 dated June, 1991, or
+ (at your option) version 3 dated 29 June, 2007.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "dnsmasq.h"
+
+#ifdef HAVE_DHCP
+
+struct iface_param {
+ struct in_addr relay, primary;
+ struct dhcp_context *current;
+ int ind;
+};
+
+static int complete_context(struct in_addr local, int if_index,
+ struct in_addr netmask, struct in_addr broadcast, void *vparam);
+
+void dhcp_init(void)
+{
+ int fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ struct sockaddr_in saddr;
+ int oneopt = 1;
+#if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
+ int mtu = IP_PMTUDISC_DONT;
+#endif
+
+ if (fd == -1)
+ die (_("cannot create DHCP socket: %s"), NULL, EC_BADNET);
+
+ if (!fix_fd(fd) ||
+#if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
+ setsockopt(fd, SOL_IP, IP_MTU_DISCOVER, &mtu, sizeof(mtu)) == -1 ||
+#endif
+#if defined(HAVE_LINUX_NETWORK)
+ setsockopt(fd, SOL_IP, IP_PKTINFO, &oneopt, sizeof(oneopt)) == -1 ||
+#else
+ setsockopt(fd, IPPROTO_IP, IP_RECVIF, &oneopt, sizeof(oneopt)) == -1 ||
+#endif
+ setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &oneopt, sizeof(oneopt)) == -1)
+ die(_("failed to set options on DHCP socket: %s"), NULL, EC_BADNET);
+
+ /* When bind-interfaces is set, there might be more than one dnmsasq
+ instance binding port 67. That's OK if they serve different networks.
+ Need to set REUSEADDR to make this posible, or REUSEPORT on *BSD. */
+ if (daemon->options & OPT_NOWILD)
+ {
+#ifdef SO_REUSEPORT
+ int rc = setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &oneopt, sizeof(oneopt));
+#else
+ int rc = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &oneopt, sizeof(oneopt));
+#endif
+ if (rc == -1)
+ die(_("failed to set SO_REUSE{ADDR|PORT} on DHCP socket: %s"), NULL, EC_BADNET);
+ }
+
+ memset(&saddr, 0, sizeof(saddr));
+ saddr.sin_family = AF_INET;
+ saddr.sin_port = htons(daemon->dhcp_server_port);
+ saddr.sin_addr.s_addr = INADDR_ANY;
+#ifdef HAVE_SOCKADDR_SA_LEN
+ saddr.sin_len = sizeof(struct sockaddr_in);
+#endif
+
+ if (bind(fd, (struct sockaddr *)&saddr, sizeof(struct sockaddr_in)))
+ die(_("failed to bind DHCP server socket: %s"), NULL, EC_BADNET);
+
+ daemon->dhcpfd = fd;
+
+#if defined(HAVE_BSD_NETWORK)
+ /* When we're not using capabilities, we need to do this here before
+ we drop root. Also, set buffer size small, to avoid wasting
+ kernel buffers */
+
+ if (daemon->options & OPT_NO_PING)
+ daemon->dhcp_icmp_fd = -1;
+ else if ((daemon->dhcp_icmp_fd = make_icmp_sock()) == -1 ||
+ setsockopt(daemon->dhcp_icmp_fd, SOL_SOCKET, SO_RCVBUF, &oneopt, sizeof(oneopt)) == -1 )
+ die(_("cannot create ICMP raw socket: %s."), NULL, EC_BADNET);
+
+ /* Make BPF raw send socket */
+ init_bpf();
+#endif
+
+ check_dhcp_hosts(1);
+
+ daemon->dhcp_packet.iov_len = sizeof(struct dhcp_packet);
+ daemon->dhcp_packet.iov_base = safe_malloc(daemon->dhcp_packet.iov_len);
+}
+
+void dhcp_packet(time_t now)
+{
+ struct dhcp_packet *mess;
+ struct dhcp_context *context;
+ struct iname *tmp;
+ struct ifreq ifr;
+ struct msghdr msg;
+ struct sockaddr_in dest;
+ struct cmsghdr *cmptr;
+ struct iovec iov;
+ ssize_t sz;
+ int iface_index = 0, unicast_dest = 0, is_inform = 0;
+ struct in_addr iface_addr, *addrp = NULL;
+ struct iface_param parm;
+
+ union {
+ struct cmsghdr align; /* this ensures alignment */
+#if defined(HAVE_LINUX_NETWORK)
+ char control[CMSG_SPACE(sizeof(struct in_pktinfo))];
+#elif defined(HAVE_SOLARIS_NETWORK)
+ char control[CMSG_SPACE(sizeof(unsigned int))];
+#elif defined(HAVE_BSD_NETWORK)
+ char control[CMSG_SPACE(sizeof(struct sockaddr_dl))];
+#endif
+ } control_u;
+
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+ msg.msg_iov = &daemon->dhcp_packet;
+ msg.msg_iovlen = 1;
+
+ while (1)
+ {
+ msg.msg_flags = 0;
+ while ((sz = recvmsg(daemon->dhcpfd, &msg, MSG_PEEK | MSG_TRUNC)) == -1 && errno == EINTR);
+
+ if (sz == -1)
+ return;
+
+ if (!(msg.msg_flags & MSG_TRUNC))
+ break;
+
+ /* Very new Linux kernels return the actual size needed,
+ older ones always return truncated size */
+ if ((size_t)sz == daemon->dhcp_packet.iov_len)
+ {
+ if (!expand_buf(&daemon->dhcp_packet, sz + 100))
+ return;
+ }
+ else
+ {
+ expand_buf(&daemon->dhcp_packet, sz);
+ break;
+ }
+ }
+
+ /* expand_buf may have moved buffer */
+ mess = (struct dhcp_packet *)daemon->dhcp_packet.iov_base;
+ msg.msg_controllen = sizeof(control_u);
+ msg.msg_control = control_u.control;
+ msg.msg_flags = 0;
+ msg.msg_name = &dest;
+ msg.msg_namelen = sizeof(dest);
+
+ while ((sz = recvmsg(daemon->dhcpfd, &msg, 0)) == -1 && errno == EINTR);
+
+ if ((msg.msg_flags & MSG_TRUNC) || sz < (ssize_t)(sizeof(*mess) - sizeof(mess->options)))
+ return;
+
+#if defined (HAVE_LINUX_NETWORK)
+ if (msg.msg_controllen >= sizeof(struct cmsghdr))
+ for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
+ if (cmptr->cmsg_level == SOL_IP && cmptr->cmsg_type == IP_PKTINFO)
+ {
+ iface_index = ((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_ifindex;
+ if (((struct in_pktinfo *)CMSG_DATA(cmptr))->ipi_addr.s_addr != INADDR_BROADCAST)
+ unicast_dest = 1;
+ }
+
+#elif defined(HAVE_BSD_NETWORK)
+ if (msg.msg_controllen >= sizeof(struct cmsghdr))
+ for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
+ if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF)
+ iface_index = ((struct sockaddr_dl *)CMSG_DATA(cmptr))->sdl_index;
+
+
+#elif defined(HAVE_SOLARIS_NETWORK)
+ if (msg.msg_controllen >= sizeof(struct cmsghdr))
+ for (cmptr = CMSG_FIRSTHDR(&msg); cmptr; cmptr = CMSG_NXTHDR(&msg, cmptr))
+ if (cmptr->cmsg_level == IPPROTO_IP && cmptr->cmsg_type == IP_RECVIF)
+ iface_index = *((unsigned int *)CMSG_DATA(cmptr));
+
+#endif
+
+ if (!indextoname(daemon->dhcpfd, iface_index, ifr.ifr_name))
+ return;
+
+#ifdef MSG_BCAST
+ /* OpenBSD tells us when a packet was broadcast */
+ if (!(msg.msg_flags & MSG_BCAST))
+ unicast_dest = 1;
+#endif
+
+ ifr.ifr_addr.sa_family = AF_INET;
+ if (ioctl(daemon->dhcpfd, SIOCGIFADDR, &ifr) != -1 )
+ {
+ addrp = &iface_addr;
+ iface_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
+ }
+
+ if (!iface_check(AF_INET, (struct all_addr *)addrp, ifr.ifr_name, &iface_index))
+ return;
+
+ for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
+ if (tmp->name && (strcmp(tmp->name, ifr.ifr_name) == 0))
+ return;
+
+ /* interface may have been changed by alias in iface_check */
+ if (!addrp)
+ {
+ if (ioctl(daemon->dhcpfd, SIOCGIFADDR, &ifr) == -1)
+ {
+ my_syslog(MS_DHCP | LOG_WARNING, _("DHCP packet received on %s which has no address"), ifr.ifr_name);
+ return;
+ }
+ else
+ iface_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
+ }
+
+ /* unlinked contexts are marked by context->current == context */
+ for (context = daemon->dhcp; context; context = context->next)
+ context->current = context;
+
+ parm.relay = mess->giaddr;
+ parm.primary = iface_addr;
+ parm.current = NULL;
+ parm.ind = iface_index;
+
+ if (!iface_enumerate(&parm, complete_context, NULL))
+ return;
+ lease_prune(NULL, now); /* lose any expired leases */
+ iov.iov_len = dhcp_reply(parm.current, ifr.ifr_name, iface_index, (size_t)sz,
+ now, unicast_dest, &is_inform);
+ lease_update_file(now);
+ lease_update_dns();
+
+ if (iov.iov_len == 0)
+ return;
+
+ msg.msg_name = &dest;
+ msg.msg_namelen = sizeof(dest);
+ msg.msg_control = NULL;
+ msg.msg_controllen = 0;
+ msg.msg_iov = &iov;
+ iov.iov_base = daemon->dhcp_packet.iov_base;
+
+ /* packet buffer may have moved */
+ mess = (struct dhcp_packet *)daemon->dhcp_packet.iov_base;
+
+#ifdef HAVE_SOCKADDR_SA_LEN
+ dest.sin_len = sizeof(struct sockaddr_in);
+#endif
+
+ if (mess->giaddr.s_addr)
+ {
+ /* Send to BOOTP relay */
+ dest.sin_port = htons(daemon->dhcp_server_port);
+ dest.sin_addr = mess->giaddr;
+ }
+ else if (mess->ciaddr.s_addr)
+ {
+ /* If the client's idea of its own address tallys with
+ the source address in the request packet, we believe the
+ source port too, and send back to that. If we're replying
+ to a DHCPINFORM, trust the source address always. */
+ if ((!is_inform && dest.sin_addr.s_addr != mess->ciaddr.s_addr) ||
+ dest.sin_port == 0 || dest.sin_addr.s_addr == 0)
+ {
+ dest.sin_port = htons(daemon->dhcp_client_port);
+ dest.sin_addr = mess->ciaddr;
+ }
+ }
+#if defined(HAVE_LINUX_NETWORK)
+ else if ((ntohs(mess->flags) & 0x8000) || mess->hlen == 0 ||
+ mess->hlen > sizeof(ifr.ifr_addr.sa_data) || mess->htype == 0)
+ {
+ /* broadcast to 255.255.255.255 (or mac address invalid) */
+ struct in_pktinfo *pkt;
+ msg.msg_control = control_u.control;
+ msg.msg_controllen = sizeof(control_u);
+ cmptr = CMSG_FIRSTHDR(&msg);
+ pkt = (struct in_pktinfo *)CMSG_DATA(cmptr);
+ pkt->ipi_ifindex = iface_index;
+ pkt->ipi_spec_dst.s_addr = 0;
+ msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
+ cmptr->cmsg_level = SOL_IP;
+ cmptr->cmsg_type = IP_PKTINFO;
+ dest.sin_addr.s_addr = INADDR_BROADCAST;
+ dest.sin_port = htons(daemon->dhcp_client_port);
+ }
+ else
+ {
+ /* unicast to unconfigured client. Inject mac address direct into ARP cache.
+ struct sockaddr limits size to 14 bytes. */
+ struct arpreq req;
+ dest.sin_addr = mess->yiaddr;
+ dest.sin_port = htons(daemon->dhcp_client_port);
+ *((struct sockaddr_in *)&req.arp_pa) = dest;
+ req.arp_ha.sa_family = mess->htype;
+ memcpy(req.arp_ha.sa_data, mess->chaddr, mess->hlen);
+ strncpy(req.arp_dev, ifr.ifr_name, 16);
+ req.arp_flags = ATF_COM;
+ ioctl(daemon->dhcpfd, SIOCSARP, &req);
+ }
+#elif defined(HAVE_SOLARIS_NETWORK)
+ else if ((ntohs(mess->flags) & 0x8000) || mess->hlen != ETHER_ADDR_LEN || mess->htype != ARPHRD_ETHER)
+ {
+ /* broadcast to 255.255.255.255 (or mac address invalid) */
+ dest.sin_addr.s_addr = INADDR_BROADCAST;
+ dest.sin_port = htons(daemon->dhcp_client_port);
+ /* note that we don't specify the interface here: that's done by the
+ IP_BOUND_IF sockopt lower down. */
+ }
+ else
+ {
+ /* unicast to unconfigured client. Inject mac address direct into ARP cache.
+ Note that this only works for ethernet on solaris, because we use SIOCSARP
+ and not SIOCSXARP, which would be perfect, except that it returns ENXIO
+ mysteriously. Bah. Fall back to broadcast for other net types. */
+ struct arpreq req;
+ dest.sin_addr = mess->yiaddr;
+ dest.sin_port = htons(daemon->dhcp_client_port);
+ *((struct sockaddr_in *)&req.arp_pa) = dest;
+ req.arp_ha.sa_family = AF_UNSPEC;
+ memcpy(req.arp_ha.sa_data, mess->chaddr, mess->hlen);
+ req.arp_flags = ATF_COM;
+ ioctl(daemon->dhcpfd, SIOCSARP, &req);
+ }
+#elif defined(HAVE_BSD_NETWORK)
+ else
+ {
+ send_via_bpf(mess, iov.iov_len, iface_addr, &ifr);
+ return;
+ }
+#endif
+
+#ifdef HAVE_SOLARIS_NETWORK
+ setsockopt(daemon->dhcpfd, IPPROTO_IP, IP_BOUND_IF, &iface_index, sizeof(iface_index));
+#endif
+
+ while(sendmsg(daemon->dhcpfd, &msg, 0) == -1 && retry_send());
+}
+
+/* This is a complex routine: it gets called with each (address,netmask,broadcast) triple
+ of each interface (and any relay address) and does the following things:
+
+ 1) Discards stuff for interfaces other than the one on which a DHCP packet just arrived.
+ 2) Fills in any netmask and broadcast addresses which have not been explicitly configured.
+ 3) Fills in local (this host) and router (this host or relay) addresses.
+ 4) Links contexts which are valid for hosts directly connected to the arrival interface on ->current.
+
+ Note that the current chain may be superceded later for configured hosts or those coming via gateways. */
+
+static int complete_context(struct in_addr local, int if_index,
+ struct in_addr netmask, struct in_addr broadcast, void *vparam)
+{
+ struct dhcp_context *context;
+ struct iface_param *param = vparam;
+
+ for (context = daemon->dhcp; context; context = context->next)
+ {
+ if (!(context->flags & CONTEXT_NETMASK) &&
+ (is_same_net(local, context->start, netmask) ||
+ is_same_net(local, context->end, netmask)))
+ {
+ if (context->netmask.s_addr != netmask.s_addr &&
+ !(is_same_net(local, context->start, netmask) &&
+ is_same_net(local, context->end, netmask)))
+ {
+ strcpy(daemon->dhcp_buff, inet_ntoa(context->start));
+ strcpy(daemon->dhcp_buff2, inet_ntoa(context->end));
+ my_syslog(MS_DHCP | LOG_WARNING, _("DHCP range %s -- %s is not consistent with netmask %s"),
+ daemon->dhcp_buff, daemon->dhcp_buff2, inet_ntoa(netmask));
+ }
+ context->netmask = netmask;
+ }
+
+ if (context->netmask.s_addr)
+ {
+ if (is_same_net(local, context->start, context->netmask) &&
+ is_same_net(local, context->end, context->netmask))
+ {
+ /* link it onto the current chain if we've not seen it before */
+ if (if_index == param->ind && context->current == context)
+ {
+ context->router = local;
+ context->local = local;
+ context->current = param->current;
+ param->current = context;
+ }
+
+ if (!(context->flags & CONTEXT_BRDCAST))
+ {
+ if (is_same_net(broadcast, context->start, context->netmask))
+ context->broadcast = broadcast;
+ else
+ context->broadcast.s_addr = context->start.s_addr | ~context->netmask.s_addr;
+ }
+ }
+ else if (param->relay.s_addr && is_same_net(param->relay, context->start, context->netmask))
+ {
+ context->router = param->relay;
+ context->local = param->primary;
+ /* fill in missing broadcast addresses for relayed ranges */
+ if (!(context->flags & CONTEXT_BRDCAST))
+ context->broadcast.s_addr = context->start.s_addr | ~context->netmask.s_addr;
+ }
+
+ }
+ }
+
+ return 1;
+}
+
+struct dhcp_context *address_available(struct dhcp_context *context,
+ struct in_addr taddr,
+ struct dhcp_netid *netids)
+{
+ /* Check is an address is OK for this network, check all
+ possible ranges. Make sure that the address isn't in use
+ by the server itself. */
+
+ unsigned int start, end, addr = ntohl(taddr.s_addr);
+ struct dhcp_context *tmp;
+
+ for (tmp = context; tmp; tmp = tmp->current)
+ if (taddr.s_addr == context->router.s_addr)
+ return NULL;
+
+ for (tmp = context; tmp; tmp = tmp->current)
+ {
+ start = ntohl(tmp->start.s_addr);
+ end = ntohl(tmp->end.s_addr);
+
+ if (!(tmp->flags & CONTEXT_STATIC) &&
+ addr >= start &&
+ addr <= end &&
+ match_netid(tmp->filter, netids, 1))
+ return tmp;
+ }
+
+ return NULL;
+}
+
+struct dhcp_context *narrow_context(struct dhcp_context *context,
+ struct in_addr taddr,
+ struct dhcp_netid *netids)
+{
+ /* We start of with a set of possible contexts, all on the current physical interface.
+ These are chained on ->current.
+ Here we have an address, and return the actual context correponding to that
+ address. Note that none may fit, if the address came a dhcp-host and is outside
+ any dhcp-range. In that case we return a static range if possible, or failing that,
+ any context on the correct subnet. (If there's more than one, this is a dodgy
+ configuration: maybe there should be a warning.) */
+
+ struct dhcp_context *tmp;
+
+ if (!(tmp = address_available(context, taddr, netids)))
+ {
+ for (tmp = context; tmp; tmp = tmp->current)
+ if (is_same_net(taddr, tmp->start, tmp->netmask) &&
+ (tmp->flags & CONTEXT_STATIC))
+ break;
+
+ if (!tmp)
+ for (tmp = context; tmp; tmp = tmp->current)
+ if (is_same_net(taddr, tmp->start, tmp->netmask))
+ break;
+ }
+
+ /* Only one context allowed now */
+ if (tmp)
+ tmp->current = NULL;
+
+ return tmp;
+}
+
+struct dhcp_config *config_find_by_address(struct dhcp_config *configs, struct in_addr addr)
+{
+ struct dhcp_config *config;
+
+ for (config = configs; config; config = config->next)
+ if ((config->flags & CONFIG_ADDR) && config->addr.s_addr == addr.s_addr)
+ return config;
+
+ return NULL;
+}
+
+/* Is every member of check matched by a member of pool?
+ If tagnotneeded, untagged is OK */
+int match_netid(struct dhcp_netid *check, struct dhcp_netid *pool, int tagnotneeded)
+{
+ struct dhcp_netid *tmp1;
+
+ if (!check && !tagnotneeded)
+ return 0;
+
+ for (; check; check = check->next)
+ {
+ if (check->net[0] != '#')
+ {
+ for (tmp1 = pool; tmp1; tmp1 = tmp1->next)
+ if (strcmp(check->net, tmp1->net) == 0)
+ break;
+ if (!tmp1)
+ return 0;
+ }
+ else
+ for (tmp1 = pool; tmp1; tmp1 = tmp1->next)
+ if (strcmp((check->net)+1, tmp1->net) == 0)
+ return 0;
+ }
+ return 1;
+}
+
+int address_allocate(struct dhcp_context *context,
+ struct in_addr *addrp, unsigned char *hwaddr, int hw_len,
+ struct dhcp_netid *netids, time_t now)
+{
+ /* Find a free address: exclude anything in use and anything allocated to
+ a particular hwaddr/clientid/hostname in our configuration.
+ Try to return from contexts which match netids first. */
+
+ struct in_addr start, addr;
+ struct dhcp_context *c, *d;
+ int i, pass;
+ unsigned int j;
+
+ /* hash hwaddr */
+ for (j = 0, i = 0; i < hw_len; i++)
+ j += hwaddr[i] + (hwaddr[i] << 8) + (hwaddr[i] << 16);
+
+ for (pass = 0; pass <= 1; pass++)
+ for (c = context; c; c = c->current)
+ if (c->flags & CONTEXT_STATIC)
+ continue;
+ else if (!match_netid(c->filter, netids, pass))
+ continue;
+ else
+ {
+ /* pick a seed based on hwaddr then iterate until we find a free address. */
+ start.s_addr = addr.s_addr =
+ htonl(ntohl(c->start.s_addr) +
+ ((j + c->addr_epoch) % (1 + ntohl(c->end.s_addr) - ntohl(c->start.s_addr))));
+
+ do {
+ /* eliminate addresses in use by the server. */
+ for (d = context; d; d = d->current)
+ if (addr.s_addr == d->router.s_addr)
+ break;
+
+ /* Addresses which end in .255 and .0 are broken in Windows even when using
+ supernetting. ie dhcp-range=192.168.0.1,192.168.1.254,255,255,254.0
+ then 192.168.0.255 is a valid IP address, but not for Windows as it's
+ in the class C range. See KB281579. We therefore don't allocate these
+ addresses to avoid hard-to-diagnose problems. Thanks Bill. */
+ if (!d &&
+ !lease_find_by_addr(addr) &&
+ !config_find_by_address(daemon->dhcp_conf, addr) &&
+ (!IN_CLASSC(ntohl(addr.s_addr)) ||
+ ((ntohl(addr.s_addr) & 0xff) != 0xff && ((ntohl(addr.s_addr) & 0xff) != 0x0))))
+ {
+ struct ping_result *r, *victim = NULL;
+ int count, max = (int)(0.6 * (((float)PING_CACHE_TIME)/
+ ((float)PING_WAIT)));
+
+ *addrp = addr;
+
+ if (daemon->options & OPT_NO_PING)
+ return 1;
+
+ /* check if we failed to ping addr sometime in the last
+ PING_CACHE_TIME seconds. If so, assume the same situation still exists.
+ This avoids problems when a stupid client bangs
+ on us repeatedly. As a final check, if we did more
+ than 60% of the possible ping checks in the last
+ PING_CACHE_TIME, we are in high-load mode, so don't do any more. */
+ for (count = 0, r = daemon->ping_results; r; r = r->next)
+ if (difftime(now, r->time) > (float)PING_CACHE_TIME)
+ victim = r; /* old record */
+ else if (++count == max || r->addr.s_addr == addr.s_addr)
+ return 1;
+
+ if (icmp_ping(addr))
+ /* address in use: perturb address selection so that we are
+ less likely to try this address again. */
+ c->addr_epoch++;
+ else
+ {
+ /* at this point victim may hold an expired record */
+ if (!victim)
+ {
+ if ((victim = whine_malloc(sizeof(struct ping_result))))
+ {
+ victim->next = daemon->ping_results;
+ daemon->ping_results = victim;
+ }
+ }
+
+ /* record that this address is OK for 30s
+ without more ping checks */
+ if (victim)
+ {
+ victim->addr = addr;
+ victim->time = now;
+ }
+ return 1;
+ }
+ }
+
+ addr.s_addr = htonl(ntohl(addr.s_addr) + 1);
+
+ if (addr.s_addr == htonl(ntohl(c->end.s_addr) + 1))
+ addr = c->start;
+
+ } while (addr.s_addr != start.s_addr);
+ }
+ return 0;
+}
+
+static int is_addr_in_context(struct dhcp_context *context, struct dhcp_config *config)
+{
+ if (!context) /* called via find_config() from lease_update_from_configs() */
+ return 1;
+ if (!(config->flags & CONFIG_ADDR))
+ return 1;
+ for (; context; context = context->current)
+ if (is_same_net(config->addr, context->start, context->netmask))
+ return 1;
+
+ return 0;
+}
+
+int config_has_mac(struct dhcp_config *config, unsigned char *hwaddr, int len, int type)
+{
+ struct hwaddr_config *conf_addr;
+
+ for (conf_addr = config->hwaddr; conf_addr; conf_addr = conf_addr->next)
+ if (conf_addr->wildcard_mask == 0 &&
+ conf_addr->hwaddr_len == len &&
+ (conf_addr->hwaddr_type == type || conf_addr->hwaddr_type == 0) &&
+ memcmp(conf_addr->hwaddr, hwaddr, len) == 0)
+ return 1;
+
+ return 0;
+}
+
+struct dhcp_config *find_config(struct dhcp_config *configs,
+ struct dhcp_context *context,
+ unsigned char *clid, int clid_len,
+ unsigned char *hwaddr, int hw_len,
+ int hw_type, char *hostname)
+{
+ int count, new;
+ struct dhcp_config *config, *candidate;
+ struct hwaddr_config *conf_addr;
+
+ if (clid)
+ for (config = configs; config; config = config->next)
+ if (config->flags & CONFIG_CLID)
+ {
+ if (config->clid_len == clid_len &&
+ memcmp(config->clid, clid, clid_len) == 0 &&
+ is_addr_in_context(context, config))
+ return config;
+
+ /* dhcpcd prefixes ASCII client IDs by zero which is wrong, but we try and
+ cope with that here */
+ if (*clid == 0 && config->clid_len == clid_len-1 &&
+ memcmp(config->clid, clid+1, clid_len-1) == 0 &&
+ is_addr_in_context(context, config))
+ return config;
+ }
+
+
+ for (config = configs; config; config = config->next)
+ if (config_has_mac(config, hwaddr, hw_len, hw_type) &&
+ is_addr_in_context(context, config))
+ return config;
+
+ if (hostname && context)
+ for (config = configs; config; config = config->next)
+ if ((config->flags & CONFIG_NAME) &&
+ hostname_isequal(config->hostname, hostname) &&
+ is_addr_in_context(context, config))
+ return config;
+
+ /* use match with fewest wildcast octets */
+ for (candidate = NULL, count = 0, config = configs; config; config = config->next)
+ if (is_addr_in_context(context, config))
+ for (conf_addr = config->hwaddr; conf_addr; conf_addr = conf_addr->next)
+ if (conf_addr->wildcard_mask != 0 &&
+ conf_addr->hwaddr_len == hw_len &&
+ (conf_addr->hwaddr_type == hw_type || conf_addr->hwaddr_type == 0) &&
+ (new = memcmp_masked(conf_addr->hwaddr, hwaddr, hw_len, conf_addr->wildcard_mask)) > count)
+ {
+ count = new;
+ candidate = config;
+ }
+
+ return candidate;
+}
+
+void dhcp_read_ethers(void)
+{
+ FILE *f = fopen(ETHERSFILE, "r");
+ unsigned int flags;
+ char *buff = daemon->namebuff;
+ char *ip, *cp;
+ struct in_addr addr;
+ unsigned char hwaddr[ETHER_ADDR_LEN];
+ struct dhcp_config **up, *tmp;
+ struct dhcp_config *config;
+ int count = 0, lineno = 0;
+
+ addr.s_addr = 0; /* eliminate warning */
+
+ if (!f)
+ {
+ my_syslog(MS_DHCP | LOG_ERR, _("failed to read %s: %s"), ETHERSFILE, strerror(errno));
+ return;
+ }
+
+ /* This can be called again on SIGHUP, so remove entries created last time round. */
+ for (up = &daemon->dhcp_conf, config = daemon->dhcp_conf; config; config = tmp)
+ {
+ tmp = config->next;
+ if (config->flags & CONFIG_FROM_ETHERS)
+ {
+ *up = tmp;
+ /* cannot have a clid */
+ if (config->flags & CONFIG_NAME)
+ free(config->hostname);
+ free(config->hwaddr);
+ free(config);
+ }
+ else
+ up = &config->next;
+ }
+
+ while (fgets(buff, MAXDNAME, f))
+ {
+ char *host = NULL;
+
+ lineno++;
+
+ while (strlen(buff) > 0 && isspace((int)buff[strlen(buff)-1]))
+ buff[strlen(buff)-1] = 0;
+
+ if ((*buff == '#') || (*buff == '+') || (*buff == 0))
+ continue;
+
+ for (ip = buff; *ip && !isspace((int)*ip); ip++);
+ for(; *ip && isspace((int)*ip); ip++)
+ *ip = 0;
+ if (!*ip || parse_hex(buff, hwaddr, ETHER_ADDR_LEN, NULL, NULL) != ETHER_ADDR_LEN)
+ {
+ my_syslog(MS_DHCP | LOG_ERR, _("bad line at %s line %d"), ETHERSFILE, lineno);
+ continue;
+ }
+
+ /* check for name or dotted-quad */
+ for (cp = ip; *cp; cp++)
+ if (!(*cp == '.' || (*cp >='0' && *cp <= '9')))
+ break;
+
+ if (!*cp)
+ {
+ if ((addr.s_addr = inet_addr(ip)) == (in_addr_t)-1)
+ {
+ my_syslog(MS_DHCP | LOG_ERR, _("bad address at %s line %d"), ETHERSFILE, lineno);
+ continue;
+ }
+
+ flags = CONFIG_ADDR;
+
+ for (config = daemon->dhcp_conf; config; config = config->next)
+ if ((config->flags & CONFIG_ADDR) && config->addr.s_addr == addr.s_addr)
+ break;
+ }
+ else
+ {
+ int nomem;
+ if (!(host = canonicalise(ip, &nomem)) || !legal_hostname(host))
+ {
+ if (!nomem)
+ my_syslog(MS_DHCP | LOG_ERR, _("bad name at %s line %d"), ETHERSFILE, lineno);
+ free(host);
+ continue;
+ }
+
+ flags = CONFIG_NAME;
+
+ for (config = daemon->dhcp_conf; config; config = config->next)
+ if ((config->flags & CONFIG_NAME) && hostname_isequal(config->hostname, host))
+ break;
+ }
+
+ if (config && (config->flags & CONFIG_FROM_ETHERS))
+ {
+ my_syslog(MS_DHCP | LOG_ERR, _("ignoring %s line %d, duplicate name or IP address"), ETHERSFILE, lineno);
+ continue;
+ }
+
+ if (!config)
+ {
+ for (config = daemon->dhcp_conf; config; config = config->next)
+ {
+ struct hwaddr_config *conf_addr = config->hwaddr;
+ if (conf_addr &&
+ conf_addr->next == NULL &&
+ conf_addr->wildcard_mask == 0 &&
+ conf_addr->hwaddr_len == ETHER_ADDR_LEN &&
+ (conf_addr->hwaddr_type == ARPHRD_ETHER || conf_addr->hwaddr_type == 0) &&
+ memcmp(conf_addr->hwaddr, hwaddr, ETHER_ADDR_LEN) == 0)
+ break;
+ }
+
+ if (!config)
+ {
+ if (!(config = whine_malloc(sizeof(struct dhcp_config))))
+ continue;
+ config->flags = CONFIG_FROM_ETHERS;
+ config->hwaddr = NULL;
+ config->domain = NULL;
+ config->next = daemon->dhcp_conf;
+ daemon->dhcp_conf = config;
+ }
+
+ config->flags |= flags;
+
+ if (flags & CONFIG_NAME)
+ {
+ config->hostname = host;
+ host = NULL;
+ }
+
+ if (flags & CONFIG_ADDR)
+ config->addr = addr;
+ }
+
+ config->flags |= CONFIG_NOCLID;
+ if (!config->hwaddr)
+ config->hwaddr = whine_malloc(sizeof(struct hwaddr_config));
+ if (config->hwaddr)
+ {
+ memcpy(config->hwaddr->hwaddr, hwaddr, ETHER_ADDR_LEN);
+ config->hwaddr->hwaddr_len = ETHER_ADDR_LEN;
+ config->hwaddr->hwaddr_type = ARPHRD_ETHER;
+ config->hwaddr->wildcard_mask = 0;
+ config->hwaddr->next = NULL;
+ }
+ count++;
+
+ free(host);
+
+ }
+
+ fclose(f);
+
+ my_syslog(MS_DHCP | LOG_INFO, _("read %s - %d addresses"), ETHERSFILE, count);
+}
+
+void check_dhcp_hosts(int fatal)
+{
+ /* If the same IP appears in more than one host config, then DISCOVER
+ for one of the hosts will get the address, but REQUEST will be NAKed,
+ since the address is reserved by the other one -> protocol loop.
+ Also check that FQDNs match the domain we are using. */
+
+ struct dhcp_config *configs, *cp;
+
+ for (configs = daemon->dhcp_conf; configs; configs = configs->next)
+ {
+ char *domain;
+
+ if ((configs->flags & DHOPT_BANK) || fatal)
+ {
+ for (cp = configs->next; cp; cp = cp->next)
+ if ((configs->flags & cp->flags & CONFIG_ADDR) && configs->addr.s_addr == cp->addr.s_addr)
+ {
+ if (fatal)
+ die(_("duplicate IP address %s in dhcp-config directive."),
+ inet_ntoa(cp->addr), EC_BADCONF);
+ else
+ my_syslog(MS_DHCP | LOG_ERR, _("duplicate IP address %s in %s."),
+ inet_ntoa(cp->addr), daemon->dhcp_hosts_file);
+ configs->flags &= ~CONFIG_ADDR;
+ }
+
+ /* split off domain part */
+ if ((configs->flags & CONFIG_NAME) && (domain = strip_hostname(configs->hostname)))
+ configs->domain = domain;
+ }
+ }
+}
+
+void dhcp_update_configs(struct dhcp_config *configs)
+{
+ /* Some people like to keep all static IP addresses in /etc/hosts.
+ This goes through /etc/hosts and sets static addresses for any DHCP config
+ records which don't have an address and whose name matches.
+ We take care to maintain the invariant that any IP address can appear
+ in at most one dhcp-host. Since /etc/hosts can be re-read by SIGHUP,
+ restore the status-quo ante first. */
+
+ struct dhcp_config *config;
+ struct crec *crec;
+
+ for (config = configs; config; config = config->next)
+ if (config->flags & CONFIG_ADDR_HOSTS)
+ config->flags &= ~(CONFIG_ADDR | CONFIG_ADDR_HOSTS);
+
+
+ if (daemon->port != 0)
+ for (config = configs; config; config = config->next)
+ if (!(config->flags & CONFIG_ADDR) &&
+ (config->flags & CONFIG_NAME) &&
+ (crec = cache_find_by_name(NULL, config->hostname, 0, F_IPV4)) &&
+ (crec->flags & F_HOSTS))
+ {
+ if (cache_find_by_name(crec, config->hostname, 0, F_IPV4))
+ {
+ /* use primary (first) address */
+ while (crec && !(crec->flags & F_REVERSE))
+ crec = cache_find_by_name(crec, config->hostname, 0, F_IPV4);
+ if (!crec)
+ continue; /* should be never */
+ my_syslog(MS_DHCP | LOG_WARNING, _("%s has more than one address in hostsfile, using %s for DHCP"),
+ config->hostname, inet_ntoa(crec->addr.addr.addr.addr4));
+ }
+
+ if (config_find_by_address(configs, crec->addr.addr.addr.addr4))
+ my_syslog(MS_DHCP | LOG_WARNING, _("duplicate IP address %s (%s) in dhcp-config directive"),
+ inet_ntoa(crec->addr.addr.addr.addr4), config->hostname);
+ else
+ {
+ config->addr = crec->addr.addr.addr.addr4;
+ config->flags |= CONFIG_ADDR | CONFIG_ADDR_HOSTS;
+ }
+ }
+}
+
+/* If we've not found a hostname any other way, try and see if there's one in /etc/hosts
+ for this address. If it has a domain part, that must match the set domain and
+ it gets stripped. The set of legal domain names is bigger than the set of legal hostnames
+ so check here that the domain name is legal as a hostname. */
+char *host_from_dns(struct in_addr addr)
+{
+ struct crec *lookup;
+ char *hostname = NULL;
+ char *d1, *d2;
+
+ if (daemon->port == 0)
+ return NULL; /* DNS disabled. */
+
+ lookup = cache_find_by_addr(NULL, (struct all_addr *)&addr, 0, F_IPV4);
+ if (lookup && (lookup->flags & F_HOSTS))
+ {
+ hostname = daemon->dhcp_buff;
+ strncpy(hostname, cache_get_name(lookup), 256);
+ hostname[255] = 0;
+ d1 = strip_hostname(hostname);
+ d2 = get_domain(addr);
+ if (!legal_hostname(hostname) || (d1 && (!d2 || !hostname_isequal(d1, d2))))
+ hostname = NULL;
+ }
+
+ return hostname;
+}
+
+/* return domain or NULL if none. */
+char *strip_hostname(char *hostname)
+{
+ char *dot = strchr(hostname, '.');
+
+ if (!dot)
+ return NULL;
+
+ *dot = 0; /* truncate */
+ if (strlen(dot+1) != 0)
+ return dot+1;
+
+ return NULL;
+}
+
+#endif
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-30 14:32:00 +0000